The present invention relates to an apparatus for developing a travelling photographic emulsion carrier, of the strip-shaped or sheet-shaped type.
It is already known in the art to provide an apparatus of this general type having a plurality of containers each accommodating a bath of a different treating liquid, for example a developer bath, a fixing bath and a washing or rinsing bath. The emulsion carrier is sequentially moved through the respective baths, travelling from one container to the next in a substantially undulate path.
This type of prior-art apparatus has certain disadvantages, resulting inter alia from the fact that the substances of some of the baths are agressive with respect to the work pieces which they contact. Furthermore, there is the danger that any one bath may become contaminated with quantities of the baths from the preceding container which adhere to the emulsion carrier and are therefore imported into the bath of the succeeding container. Also, the moist photographic emulsion layers are highly susceptible to mechanical damage and the emulsion carrier itself is hygroscopic, a characteristic which tends to cause an expansion of the emulsion carrier in lengthwise direction as the carrier is being transported through the apparatus.
There is nothing in the prior art to provide satisfactory solutions to these problems. Such attempts as have been made to overcome the difficulties have had to be made at the expense of ease of operation and maintenance of the apparatus so that by providing partial solutions to one set of problems an entire new set of difficulties was created. Moreover, it was heretofore found to be impossible to prevent mechanical damage to the emulsion carrier due to rubbing of the emulsion carrier against the guide baffles employed in the prior-art apparatus and no solution has been found to prevent the undesired transfer of liquid from one bath into the liquid of a different secreting bath.
Another problem which exists, but has not even been considered in the prior art, is the fact that guide rollers guiding the emulsion carrier for the respective bath tend to have a film of the bath liquid dry on their circumferential surfaces, i.e., on those portions of the circumferential surfaces which are located in the atmosphere and not immersed in the bath liquid, if the rollers stand still for a period of time, for example during machine down-time.